The present invention concerns a leveling device that is configured to be integrated with, or attached to, an object, such as a chair, bucket, table, jack or other object, in order to keep the object level when placed on an uneven or a non-level surface.
Many objects require an even, level underlying surface for optimal use. For example, objects such as chairs, buckets, tables, ladders, scaffolding, jacks, barbeque grills and portable stairs are designed with the assumption that the object will be placed on an even, level underlying surface. However, when such objects are used outdoors, rarely is such an underlying surface available. Thus, using such products outdoors oftentimes involves the challenging and frustrating search for a suitable area of land.
As but one example, participants and spectators of various outdoor activities, such as sporting events, fireworks displays, fishing derbies, parades, etc. typically use traditional folding lawn chairs for seating during such activities. Traditional folding lawn chairs typically include a three piece frame comprised of an integral hinged seating platform and back support, along with two foldable leg assemblies. The leg assemblies generally include front and rear horizontal support bars made of tubular aluminum and configured to engage the ground in order to support the chair in a stable manner.
Such folding lawn chairs commonly are placed on soft, grassy areas that may or may not be flat. Hard rocky and gravelly surfaces typically are avoided because such surfaces interact poorly with the rigid metal support bars of the chair, leading to unintended rocking and wobbling of the chair, and a general feeling of instability and discomfort by the user of the chair.
Additionally, uneven and sloping terrains often times are avoided because the design of such chairs assumes that the chairs will be used on level surfaces and does not provide a means for adjusting the pitch of the chair seating platform to account for such terrains.
That is, the seating platform of most traditional folding lawn chairs remains roughly parallel relative to the ground only when the ground is generally flat and level. As the slope of the ground changes, the angle of the seating platform relative to the vertical and horizontal axes of the ground changes, either decreasing or increasing.
When the angle of the seating platform decreases relative to the horizontal axis of the ground, the user of the chair fights the force of being pushed forward and out of the chair. When the angle of the seating platform increases relative to the horizontal axis of the ground, the user of the chair is forced backwards into the chair, sometimes uncomfortably so. On particularly steep slopes, there is the possibility that the chair could slide or topple.
Similarly, when the angle of the seating platform decreases relative to the vertical axis of the ground, the user of the chair fights the force of being pushed to left. When the angle of the seating platform increases relative to the vertical axis of the ground, the user of the chair fights the force of being pushed to the right.
At some point of frustration and/or discomfort, users may elect to sit directly on the ground, even though it may negatively affect the user's view of the activities being viewed or soil the user's clothing, in the case of dirty, muddy or wet ground.
The prior art has made numerous attempts to solve this problem. However, each of these attempts has shortcomings, which prevent them from fully achieving a practical solution to the problem, especially a solution that can be used across many types of objects, not just chairs.
For example, Alexander, Jr., U.S. Pat. No. 6,871,911, discloses a folding chair having a pair of adjustable, telescoping rear legs. The legs can be extended or retracted to allow the chair to sit on both level and sloping ground. A clamping device holds the retractable legs in place. However, the Alexander, Jr. device is not designed to be used on highly uneven surfaces, and its limited number of ground contact points may adversely affect its stability.
Wilson, U.S. Pat. No. 5,494,333, teaches a lawn chair, again configured to be used on sloping terrain. The chair includes three adjustable, telescoping legs that can be extended or retracted and locked into the desired position. Additionally, each leg includes a leveling foot that conforms to the slope of the terrain. However, like the Alexander, Jr. device, the Wilson chair is not designed to be used on highly uneven surfaces and the limited number of ground contact points does not maximize the chair's stability on particularly uneven surfaces.
Barnett, U.S. Pat. No. 6,905,172, discloses a chair having multiple, adjustable legs, each leg having a footer attached to the leg using a ball-and-socket-type connection. The legs may be extended or retracted and the footer may be adjusted to match the slope of the surface. However, like the previous adjustable chair patents, the number of ground contact points is small and, thus, the stability of the chair is not maximized.
In yet another example of the prior art, Shank, U.S. Pat. No. 6,036,148, teaches a folding lawn chair having independently adjustable mechanisms attached to each leg of the lawn chair that allow the lawn chair to be used on uneven ground. A clamping mechanism secures the telescoping mechanisms, which essentially comprise telescoping legs, to the regular tubular frame members of the chair. However, like the inventions disclosed in the previously discussed prior art patents, the chair in Shank is not designed to be used on highly uneven surfaces because it does not maximize the ground contact points.
U.S. Pat. No. 5,364,163 to Hardison discloses a fishing chair with adjustable legs. The legs are vertically adjustable and include spikes for engaging the ground. The legs are locked into place using spring-biased pins that engage holes formed in the legs. Because the device taught by the Hardison patent uses the same type of horizontal support bar that is found in traditional prior art folding chairs, it does not solve the problem of using such chairs on highly irregular surfaces.
As noted above, while chairs comprise one of the most commonly used outdoor devices for which a level surface provides for optimal use, there are a host of other devices for which an even, level underlying surface is preferred. Such devices include, for example, buckets, tables, ladders, scaffolding, jacks, barbeque grills and portable stairs. The prior art has developed various means in an attempt to provide such devices with the ability to be used on uneven surfaces.
For example, a number of devices have been developed to keep such objects level. U.S. Pat. No. 6,213,436 to Hembree, U.S. Pat. No. 6,935,644 to Oranday, and U.S. Pat. No. 2,913,207 to Eash each disclose a platform or container for holding another object (a bucket, a cooler, a camping grill, etc.). Each patent discloses a structure with vertically adjustable legs that may be extended and locked into place to level the platform/container with respect to a sloped surface. However, much like the prior art developed with respect to foldable lawn chairs (as discussed above) none of the inventions disclosed in these patents provide maximum stability on uneven surfaces, because the number of ground contact points is not maximized.
Lastly, U.S. Pat. No. 6,702,066 to Eaton teaches a ladder having slidable extensions fitted to the legs of the ladder and secured with bolts and wing nuts. The length of the legs may be independently adjusted. While the ladder is configured to be used on uneven surfaces, the adjustment means does not permit the ladder to be used on highly uneven surface. Moreover, the limited number of ground contact points does not maximize stability.
Therefore, a need exists for a leveling device that can be attached to or integrated with a wide variety of objects that are used outdoors and that are designed to be optimally used on level surfaces, such as a chairs, buckets, tables, jacks or other objects, in order to keep such objects level when placed on an uneven or a non-level surface. Preferably, such a leveling device can be used with a wide variety of objects. More preferably, such a leveling device can additionally act as a height adjustment mechanism to adjust the height of the objects. More preferably still, such a leveling device has numerous ground contact points to provide maximum stability. Most preferably, each individual ground contact point is independently adjustable so as to provide a near infinite level of adjustability and to customize the ground contact points to the contour of the ground.